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Topic: Penguins (Read 23744 times)

They are extraordinarily like children, these little people of the Antarctic world, either like children, or like old men, full of their own importance and late for dinner, in their black tail-coats and white shirt-fronts ÃƒÂ¢Ã¢â€šÂ¬Ã¢â‚¬Â and rather portly withal.

Well, fish is their main diet....so yup, i'd say lil old men! Sounds about right. Huddled little old men, with a bad sense of humour, laughing raucously, and eating fish....anyone see the connection? Anyone? No just me then...

1 . Penguins eat krill (a shrimplike crustacean in the family Euphausiidae), squids, and fishes. Various species of penguins have slightly different food preferences, which reduces competition among species.

2. The smaller penguin species of the Antarctic and the subantarctic primarily feed on krill and squids. Species found farther north tend to eat fishes.

1 . Penguins feed at sea. Most feeding occurs within 15.3 to 18.3 m (50-60 ft.) of the surface. The location of prey can vary seasonally and even daily.

2. Penguins primarily rely on their vision while hunting. It is not known how penguins locate prey in the darkness, at night, or at great depths, but some scientists hypothesize that penguins are helped by the fact that many oceanic squids, crustaceans, and fishes are bioluminescent (they produce light).

3. Penguins catch prey with their bills and swallow it whole while swimming. Penguins have a spiny tongue and powerful jaws to grip slippery prey.

4. Different species travel various distances from the colony in search of food.

a. Penguins fast for prolonged periods during breeding seasons; they do not leave nesting areas to feed. Some penguins fast throughout the entire courtship, nesting, and incubation periods.

b. Penguins also fast during annual molting periods. The temporary reduction in insulation and waterproofing caused by the loss of feathers during a molt prohibits penguins from entering the water to feed. Their fat layer provides energy until the molt is over ..c. Chicks fast near the time they are ready to shed juvenile feathers for adult plumage. Usually by this time, the parents no longer are feeding the chick. Growth stops during this fasting period, but resumes once the molt is complete.

2. The length of fasting depends on penguin species, sex, and type of fasting. The king and emperor penguins have the longest fasting periods.

a. Breeding male king penguins may fast for up to 54 days during courtship and the first incubation shift.

b. Breeding male emperor penguins may fast 90 to 120 days during courtship, breeding, and the entire incubation period.

5. Although king penguins are highly gregarious at rookery sites throughout the year, they usually travel in small groups of 5 to 20 individuals.

6. Penguins communicate by vocalizing and performing physical behaviors called "displays." They use many vocal and visual displays to communicate nesting territories and mating information. They also use displays in partner and chick recognition, and defense against intruders.

1. Penguin calls (vocalizations) are individually identifiable, allowing partners to recognize each other and also their chick. This is important since the members of a large colony of penguins are nearly indistinguishable on sight .

2. Research has identified differences in the calls of male and female emperor penguins. These differences probably function in courtship and mate selection.

3. There are three main kinds of penguin calls.

a. The contact call is usually used at sea to assist in visual recognition of colony members. The contact call of emperor and king penguins can be heard one kilometer (0.6 mi.) .

b. The display call is the most complex of all the calls and is used between partners in a colony. The call must convey information on territorial, sexual, and individual recognition.

c. The threat call is the simplest and is used to defend a territory and warn against predators

emperor Aptenodytes forsteri size: 11 2 cm (44 in.), 27 to 41 kg (60-90 lb.) distribution: circumpolar on Antarctic continent within limits of pack-ice (Marchant, 1990); one of two species restricted to the Antarctic (the other is the Adelie); generally avoid open water beyond limits of floating ice (Marchant, 1990). population: 135,000 to 175,000 pairs current status: not globally threatened, stable with some local fluctuations

size: 56 to 66 cm (22-26 in.), 4 kg (9 lb.) distribution: islands off the west coast of South America and along the coast of Peru and Chile population: 20,000 total birds current status: insufficiently known (IUCN Red List of Threatened Animals), CITES I

size: 53 cm (21 in.), 2.5 kg (5-6 lb.) distribution: Galapagos Islands, off the coast of Ecuador, almost astride the equator; is the most northerly penguin species population: 6,000 to 15,000 total birds current status: endangered (U.S. Fish and Wildlife Service Endangered Species List)

Is there anyone that knows of another kind? Do not be shy, step forward!

An interesting taxonomy...Yet hopelessly unschooled in the true subtleties of Penguin ranks and racial interaction, and of course unknowing of the true Penguin social structure.Perhaps I should endeavour to enlighten them.

1. All adult penguins are countershaded; that is they are dark on their dorsal (back) surfaces and white on their ventral (underside) surfaces. The dark dorsal side blends in with the dark ocean depths when viewed from above. The light ventral side blends in with the lighter surface of the sea when viewed from below. The result is that predators or prey do not see a contrast between the countershaded animal and the environment.

2. Many species have distinct markings and coloration.

a. The emperor has a black head, chin, and throat with broad yellow ear patches on the sides of the head.

b. The king penguin has a black head, chin, and throat with vivid orange, tear-shaped ear patches. The orange coloration extends to the upper chest.

1 . Different species of penguins can be identified by their head and facial markings.

2. Penguins have a variety of bill shapes which are used to capture fish, squid, and crustaceans. Generally, the bill tends to be long and thin in species that are primarily fish eaters, but shorter and stouter in those that mainly feed on krill. The mouth is lined with horny, rear-directed spines to aid in swallowing live prey.

3. Eyes.

a. The color of irises varies among the species.

(1) Many species have brown, reddish-brown, or golden-brown eyes.

(2) Rockhopper and macaroni penguins have red eyes.

(3) Fairy (little blue) penguins have bluish-gray eyes.

(4) As their name implies, yellow-eyed penguins have yellow eyes.

b. The pupil of a penguin eye is circular. When constricted, however, the pupil of the king penguin is square.

c. Like many animals, penguins have a nictitating membrane, sometimes called a third eyelid. This is a clear covering that protects the eye from injury.

1. Penguin legs are short and strong. Feet are webbed, with visible claws. The legs are set far back on the body to aid in streamlining and steering while swimming. This placement also causes penguins to stand vertically and walk upright.

1. Shiny feathers uniformly overlap to cover a penguin's skin. Feathers are highly specialized-short, broad, and closely spaced, helping to keep water away from the skin. Tufts of down on the feather shafts contribute to the insulative properties of the feathers.

2. Penguins have more feathers than most other birds, with about 70 feathers per square inch.

3. Most penguin species go through one complete molt (shed their feathers) each year, usually after the breeding season. The exception is the Galapagos penguin, which usually goes through two molts annually.

a. Molting is an essential function, as feathers wear out during the year. Feathers become worn when penguins rub against each other, come in contact with the ground and water, and regularly preen (clean, rearrange, and oil) their feathers.

b. The new feather grows under the old one, pushing it out. The old feather does not fall out until the new one is completely in place. The molt is patchy and can give individual penguins a scruffy look.

c. During the molt, feathers lose some of their insulating and waterproofing capabilities, and penguins stay out of the water until their plumage is restored to optimum condition.

d. Depending on the species, the average length of the molt varies from 13 days for the Galapagos penguin to 34 for the emperor penguin.

e. Because penguins don't enter the water to feed during a molt, they fast. Before their molt, they build a fat layer, which provides energy until the molt is over.

1 . Generally, penguins are not sexually dimorphic; males and females look alike. Crested penguins are exceptions: the males are more robust and have larger bills.

2. During the breeding season, female penguins are sometimes identifiable by muddy footprints on their backs, left by males during mating activity.

1. Incubation is the time spent warming the egg before it hatches. With the exception of emperor penguins, partners take turns incubating eggs, allowing each mate to leave to feed for several days at a time.

2. A female emperor penguin transfers a single egg to the top of her mate's feet. The female goes to sea to feed while the male incubates the egg alone. She returns several weeks later, usually just before the egg is ready to hatch, to relieve her mate so that he may feed. The male fasts throughout the courtship, nesting, and incubation periods. He will live off reserves of body fat which may be 3 to 4 cm (1.2-1.6 in.) thick, losing up to 45% of his body weight.

3. The incubation period varies with species. It may be as short as one month, as in the erect-crested penguins, or as long as 62 to 66 days for the emperors.

4. The incubation temperature for penguins is approximately 36Ãƒâ€šÃ‚Â°C (96.5Ãƒâ€šÃ‚Â°F); it is a bit lower for the larger species. Emperor penguins can maintain an incubation temperature of 31Ãƒâ€šÃ‚Â°C (87.8Ãƒâ€šÃ‚Â°F) in an environment that is -60Ãƒâ€šÃ‚Â°C (-76Ãƒâ€šÃ‚Â°F)

5. The greatest single cause for reproductive failure in some species is the mistiming between parents of nest relief during incubation. This usually occurs when the female fails to return from a foraging trip before the male deserts the nest. A male will spontaneously leave the nest and eggs when the motivation to feed overcomes that for incubating the eggs.

1. A fine down covers most newly hatched chicks. (King penguin chicks hatch naked and grow down within a few weeks.)

a. Down feathers of different species may be white, gray, black, or brown.

b. Down feathers are not waterproof, and chicks must remain out of the water until they acquire their juvenile plumage. Adult plumage is acquired at about one year.

2. In all species, the coloration and markings of chicks separate them from adults. Scientists believe that adult penguins do not perceive the young birds as competitors for mates or nesting sites. The chicks'coloration may elicit parental behavior from the adults instead.

Emperor chicks have striking facial markings.

3. The striking markings of emperor chicks may help to make the chicks more visible against the ice and snow; significant because emperors don't have individual nest sites where the young can be found.